Data Warehousing products
Home Page......
Informatica
Terradata
                                                          Informatica



1. While importing the relational source definition from database, what are the metadata of source U import?

      Source name
       Database location
       Column names
       Data types
      Key constraints

2. How many ways U can update a relational source definition and what r they?
      Two ways
           1. Edit the definition
           2. Re import the definition

3. Where should U place the flat file to import the flat file definition to the designer?

     Place it in local folder

4. To provide support for Mainframes source data, which files r used as a source definitions?
      COBOL files
5. Which transformation should u need while using the COBOL sources as source definitions?
Normalizer transformation which is used to normalize the data. Since COBOL sources r often consists of Denormailzed data.

6. How can U create or import flat file definition in to the warehouse designer?

   U can not create or import flat file definition in to warehouse designer directly. Instead U must analyze the file in source analyzer, and then drag it into the warehouse designer. When u drags the flat file source definition into warehouse designer workspace, the warehouse designer creates a relational target definition not a file definition. If u want to load to a file, configure the session to write to a flat file. When the informatica server runs the session, it creates and loads the flat file.

7. What is the maplet?   Maplet is a set of transformations that you build in the maplet designer and U can use in multiple mappings.

8. What is a transformation?  It is a repository object that generates, modifies or passes data.

9. What r the designer tools for creating transformations?
   Mapping designer
   Transformation developer
   Mapplet designer

10. What r the active and passive transformations?
       An active transformation can change the number of rows that pass through it. A passive transformation does not change the number of rows that pass through it.

11. What r the connected or unconnected transformations?
     An unconnected transforamtion is not connected to other transformations in the mapping.Connected transforamation is connected to other transforamtions in the mapping.

12. How many ways u create ports?
         Two ways
          1.Drag the port from another transforamtion
          2.Click the add buttion on the ports tab.

14. What r the reusable transforamtions?
       Reusable transformations can be used in multiple mappings.When u need to incorporate this transformation  into maping,U add an instance of it to maping.Later if U change the definition of the transformation ,all instances of it inherit the changes.Since the instance of reusable transforamation is a pointer to that transforamtion,U can change the transforamation in the transformation developer,its instances automatically reflect these  changes.This feature can save U great deal of work.

15. What r the methods for creating reusable transforamtions?
        Two methods
         1.Design it in the transformation developer.
         2.Promote a standard transformation from the mapping designer.After U add a transformation to the mapping , U can promote it to the status of reusable transformation.
     Once U promote a standard transformation to reusable status,U can demote it to a standard transformation at any time.
    If u change the properties of a reusable transformation in mapping,U can revert it to the original reusable transformation properties by clicking the revert button.

16.What r the unsupported repository objects for a mapplet?
      COBOL source definition
      Joiner transformations
      Normalizer transformations
      Non reusable sequence generator transformations.
      Pre or post session stored procedures
      Target defintions
      Power mart 3.5 style Look Up functions
      XML source definitions
      IBM MQ source defintions

17. What r the mapping paramaters and maping variables?
      Maping parameter represents a constant value that  U can define before running a session.A mapping parameter retains the same value throughout the entire session.
     When u use the maping parameter ,U declare and use the parameter in a maping or maplet.Then define the value of parameter in a parameter file for the session.
   Unlike  a mapping parameter,a maping variable represents a value that can change throughout the session.The informatica server saves the value of maping variable to the repository at the end of session run and uses that value  next time U run the session.

18. Can U use the maping parameters or variables created in one maping into another maping? NO.
We can use mapping parameters or variables in any transformation of the same maping or mapplet in which U have created maping parameters or variables.
19.Can u use the  maping parameters or variables created in one maping into any other reusable transformation?
    Yes.Because reusable tranformation is not contained with any maplet or maping.

20.How can U improve session performance in aggregator transformation?    Use sorted input.

21.What  is aggregate cache in aggregator transforamtion?
       The aggregator stores data in the aggregate cache until it completes aggregate calculations.When u run a session that uses an aggregator transformation,the informatica server creates index and data caches in memory to process the transformation.If the informatica server requires more space,it stores overflow values in cache files.

22.What r the diffrence between joiner transformation and source qualifier transformation?
       U can join hetrogenious data sources in joiner  transformation which we can not achieve in source qualifier transformation.
      U need matching keys to join two  relational sources in source qualifier transformation.Where as u doesn't need matching keys to join two sources.
     Two relational sources should come from same datasource  in sourcequalifier.U can join relatinal sources which r coming from diffrent sources also.

23.In which condtions we can not use joiner transformation(Limitaions of joiner transformation)?

Both pipelines begin with the same original data source.
Both input pipelines originate from the same Source Qualifier transformation.
Both input pipelines originate from the same Normalizer transformation.
Both input pipelines originate from the same Joiner transformation.
Either input pipelines contains an Update Strategy transformation.
Either input pipelines contains a connected or unconnected Sequence Generator transformation.

24. What r the settings that u use to configure the joiner transformation?
 Master and detail source
Type of join    
Condition of the join

25. What r the join types in joiner transformation?
      Normal (Default)
      Master outer
      Detail outer
      Full outer
26.What r the joiner caches?
     When a Joiner transformation occurs in a session, the Informatica Server reads all the records from the master source and builds index and data caches based on the master rows.
After building the caches, the Joiner transformations reads records from the detail source and perform joins.

27. What is the look up transformation?
      Use lookup transformation in u'r mapping to lookup data in a relational table, view, synonym.
      Informatica server queries the look up table based on the lookup ports in the transformation. It compares the lookup transformation port values to lookup table column values based on the look up condition.
28.Why use the lookup transformation ?
      To perform the following tasks.
Get a related value. For example, if your source table includes employee ID, but you want to include the employee name in your target table to make your summary data easier to read.
Perform a calculation. Many normalized tables include values used in a calculation, such as gross sales per invoice or sales tax, but not the calculated value (such as net sales).
Update slowly changing dimension tables. You can use a Lookup transformation to determine whether records already exist in the target.

29.What r the types of lookup?            Connected and unconnected

30.Differences between connected and unconnected lookup?

          Connected lookup                                                     Unconnected lookup

    Receives input values diectly from                       Receives input values from the result of a
    the pipe line.                                                       lkp expression in a another transformation.

   U can use a dynamic or static cache                    U can use a static cache.

    Cache includes all lookup columns                  Cache includes all lookup out put ports in the
  used in the mapping                                            lookup condition and the lookup/return port.

   Support user defined default values                  Does not support user defiend default values

31.what is meant by lookup caches?

    The informatica server builds a cache in memory when it processes the first row af a data in a cached  look up transformation.It allocates memory for the cache based on the amount u configure in the transformation or session properties.The informatica server stores condition values in the index cache and output values in the data cache.

32. What r the types of lookup caches?

     Persistent cache: U can save the lookup cache files and reuse them the next time the informatica server processes a lookup transformation configured to use the cache.

Recache from database: If the persistent cache is not synchronized with he lookup table,U can configure the lookup transformation to rebuild  the lookup cache.

Static cache: U can configure a static or read-only cache for only lookup table. By default informatica server creates a static cache.It caches the lookup table and lookup values in the cache for each row that comes into the transformation.when the lookup condition is true,the informatica server does not update the cache while it prosesses the lookup transformation.

Dynamic cache: If u want to cache the target table and insert new rows into cache  and the target,u can create a look up transformation to use dynamic cache.The informatica server dynamically inerts data to the target table.

shared cache: U can share the lookup cache between multiple transactions.U can share unnamed cache between transformations inthe same maping.

33. Difference between static cache and dynamic cache

    Static cache                                                                  Dynamic cache

 U can not inert or update the cache.                    U can insert rows into the cache as u pass 
                                                                          to the target 
The informatic server returns a value from           The informatic server inserts rows into cache
the lookup table opr cache when the condition       when the condition is false.This indicates that
is true.When the condition is not true,the               the row is not in the cache or target table.
informatica server returns the default value           U can pass these rows to the target table.
 for connected transformations and null for
unconnected transformations.


34. Which transformation should we use to normalize the COBOL and relational sources?
    Normalizer Transformation.
      When U drag the COBOL source in to the mapping Designer workspace,the normalizer transformation automatically appears,creating input and output ports for every column in the source.

35.How the informatica server sorts the string values in Ranktransformation?
    When the informatica server runs in the ASCII data movement mode it sorts session data using  Binary sortorder.If U configure the seeion to use a binary sort order,the informatica server caluculates the binary value of each string and returns the specified number of  rows   with the higest binary values for the string.

36.What r the rank caches?

    During the session ,the informatica server compares an inout row with rows in the datacache.If the input row out-ranks a stored row,the informatica server replaces the stored row with the input row.The informatica server stores group information in an index cache and row data in a data cache.

37.What is the Rankindex in Ranktransformation?

    The Designer automatically creates a RANKINDEX port for each Rank transformation. The Informatica Server uses the Rank Index port to store the ranking position for each record in a group. For example, if you create a Rank transformation that ranks the top 5 salespersons for each quarter, the rank index numbers the salespeople from 1 to 5:

38.What is the Router transformation?

     A Router transformation is similar to a Filter transformation because both transformations   allow you to use a condition to test data. However, a Filter transformation tests data for one condition and drops the rows of data that do not meet the condition. A Router transformation tests data for one or more conditions and gives you the option to route rows of data that do not meet any of the conditions to a default output group.
 If you need to test the same input data based on multiple conditions, use a Router Transformation in a mapping instead of creating multiple Filter transformations to perform the same task.

39.What r the types of  groups in Router transformation?   Input group    Output group

    The designer copies property information from the input ports of the input group to create a set  of output ports for each output group.
   Two types of output groups
      User defined groups
      Default group
      U can not modify or delete default groups.

40.Why we use stored procedure transformation?     For populating and maintaining data bases.

42.What r the types of data that passes between informatica server and stored procedure?
         3 types of data
                     Input/Out put parameters
                     Return Values
                     Status code.
43.What is the status code?

           Status code provides error handling for the informatica server during the session.The stored procedure issues a  status code that notifies whether or not stored procedure completed sucessfully.This value can not seen by the user.It only used by the informatica server to determine whether to continue running the session or stop.

44. What is source qualifier transformation?

      When U add a relational or a flat file source definition to a maping,U need to connect it to
     a source qualifer transformation.The source qualifier transformation represnets the records
   that the informatica server reads when it runs a session.

45.What r the tasks that source qualifier performs?

     Join  data originating from same source data base.
     Filter records when the informatica server reads source data.
     Specify an outer join rather than the default inner join
     specify sorted records.
     Select only distinct values from the source.
     Creating custom query to issue a special SELECT statement for the informatica server to read
      source data.

46. What is the target load order?

      U specify the target loadorder based on source qualifiers in a maping.If u have the multiple
      source qualifiers connected to the multiple  targets,U can designatethe order in which informatica
      server loads data into the targets.

47.What is the default join that source qualifier provides?

     Inner equi join.

48. What r the basic needs to join two sources in a source qualifier?

       Two sources should have primary and Foreign key relation ships.
       Two sources should have  matching data types.

49.what is update strategy transformation ?

     This transformation is used to maintain the history data or just most recent changes in to target
    table.

50.Describe two levels in which update strategy transformation sets?

   Within a session. When you configure a session, you can instruct the Informatica Server to either treat all records in the same way (for example, treat all records as inserts), or use instructions coded into the session mapping to flag records for different database operations.

Within a mapping. Within a mapping, you use the Update Strategy transformation to flag records for insert, delete, update, or reject.

51.What is the default source option for update stratgey transformation?

        Data driven.

52. What is Datadriven?

          The informatica server follows instructions coded into update strategy transformations with
        in the session maping determine how to flag records for insert,update,,delete  or reject
        If u do not choose data driven  option setting,the informatica server ignores all update strategy
       transformations in the mapping.

53.What r the options in the target session of  update strategy transsformatioin?

      Insert
      Delete
      Update
      Update as update
      Update as insert
      Update esle insert
      Truncate table

54. What r the types of maping wizards that r to be provided in Informatica?

      The Designer provides two mapping wizards to help you create mappings quickly and easily. Both wizards are designed to create mappings for loading and maintaining star schemas, a series of dimensions related to a central fact table.

 Getting Started Wizard. Creates mappings to load static fact and dimension tables, as well as slowly growing dimension tables.
Slowly Changing Dimensions Wizard. Creates mappings to load slowly changing dimension tables based on the amount of historical dimension data you want to keep and the method you choose to handle historical dimension data.

55. What r the types of maping in Getting Started Wizard?

      Simple Pass through maping :

      Loads a static fact or dimension table by inserting all rows. Use this mapping when you want to drop all existing data from your table before loading new data.

   Slowly Growing target :

     Loads a slowly growing fact or dimension table by inserting new rows. Use this     mapping to load new data when existing data does not require updates.

56. What r the mapings that we use for slowly changing  dimension table?

      Type1:  Rows containing changes to existing dimensions are updated in the target by overwriting the existing dimension. In the Type 1 Dimension mapping, all rows contain current dimension data.
   Use the Type 1 Dimension mapping to update a slowly changing dimension table when you do not need to keep any previous versions of dimensions in the table.

 Type 2:  The Type 2 Dimension Data mapping inserts both new and changed dimensions into the target. Changes are tracked in the target table by versioning the primary key and creating a version number for each dimension in the table. 
  Use the Type 2 Dimension/Version Data mapping to update a slowly changing dimension table when you want to keep a full history of dimension data in the table. Version numbers and versioned primary keys track the order of changes to each dimension.

Type 3: The Type 3 Dimension mapping filters source rows based on user-defined comparisons and inserts only those found to be new dimensions to the target. Rows containing changes to existing dimensions are updated in the target. When updating an existing dimension, the Informatica Server saves existing data in different columns of the same row and replaces the existing data with the updates

57.What r the different types of Type2 dimension maping?

       Type2 Dimension/Version Data Maping: In this maping the updated dimension in the                source  will gets inserted in target along with a new version number.And newly added dimension
in source will inserted into target with a primary key.

 Type2  Dimension/Flag current Maping: This maping is also used for slowly changing dimensions.In addition it creates a flag value for changed or new dimension.
  Flag indiactes the dimension is new or newlyupdated.Recent dimensions will gets saved with cuurent flag value 1. And updated dimensions r saved with the value 0.

Type2  Dimension/Effective Date Range Maping: This is also one flavour of Type2 maping used for slowly changing dimensions.This maping also inserts both new and changed dimensions in to the target.And changes r tracked by the effective date range for each version of each dimension.

58.How can u recognise whether or not the newly added rows in the source r gets insert in the target ?

    In the Type2 maping we have three options to recognise the newly added rows
     Version number
     Flagvalue
     Effective date Range

59. What r two types of processes that informatica runs the session?

  Load manager Process: Starts the session, creates the DTM process, and sends post-session email when the session completes.
 The DTM process. Creates threads to initialize the session, read, write, and transform data, and handle pre- and post-session operations.

60. What r the new features of the server manager in the informatica 5.0?

         U can use command line arguments for a session or batch.This allows U to change the values of session parameters,and mapping parameters and maping variables.

   Parallel data processig: This feature is available for powercenter only.If we use the informatica server on a SMP system,U can use multiple CPU's to process a session concurently.

Process session data using threads: Informatica server runs the session in two processes.Explained in previous question.

61. Can u generate reports in Informatcia?

     Yes. By using  Metadata reporter we can generate reports in informatica.

62.What is metadata reporter?

       It is a web based application that enables you to run reports againist repository metadata.
    With a meta data reporter,u can access information about U'r repository with out having knowledge of sql,transformation language or underlying tables in the repository.

63.Define maping and sessions?

      Maping: It is a set of source and target definitions linked by transformation objects that define the rules for transformation.
  Session : It is a set of instructions that describe how and when to move data from source to targets.

64.Which tool U use to create and manage sessions and batches and to monitor and stop the informatica server?

      Informatica server manager.

65.Why we use partitioning the session in informatica?

        Partitioning achieves the session performance by reducing the time period of reading the source and loading the data into target.

66.To achieve the session partition  what r the necessary tasks u have to do?

          Configure the session to partition source data.

          Install the informatica server on a machine with multiple CPU's.

67.How the informatica server increases the session performance through partitioning the source?

   For a relational sources informatica server creates multiple connections for each parttion of  a single source and extracts seperate range of data for each connection.Informatica server reads multiple partitions of a single source concurently.Similarly for loading also informatica server creates multiple connections to the target and loads partitions of data concurently.

   For XML and file sources,informatica server reads multiple files concurently.For loading the data informatica server creates a seperate file for each partition(of a source file).U can choose to merge the targets.

68. Why u use repository connectivity?

       When u edit,schedule the sesion each time,informatica server directly communicates the repository to check whether or not the session and users r valid.All the metadata of sessions and mappings will be stored in repository.

69.What r the tasks that Loadmanger process will do?

     Manages the session and batch scheduling: Whe u start the informatica server the load maneger launches and queries the repository for  a list of sessions configured to run on the informatica server.When u configure the session the loadmanager maintains list of list of sessions and session start times.When u sart a session loadmanger fetches the session information from the repository to perform the validations and verifications prior to starting DTM process.

Locking and reading the session: When the informatica server starts a session lodamaager locks the session from the repository.Locking prevents U starting the session again and again.

Reading the parameter file: If the session uses a parameter files,loadmanager reads the parameter file and verifies that the session level parematers are declared in the file

Verifies permission and privelleges: When the sesson  starts load  manger checks whether or not the user have privelleges to run the session.

Creating log files: Loadmanger creates logfile contains the status of session.

70. What is DTM process?

    After the loadmanger performs validations for session,it creates the DTM process.DTM is to create and manage the threads that carry out the session tasks.I creates the master thread.Master thread creates and manges all the other threads.

71. What r the different threads in DTM process?

   Master thread: Creates and manages all other threads

  Maping thread: One maping thread will be creates for each session.Fectchs session and maping information.

Pre and post session threads: This will be created to perform pre and post session operations.

Reader thread: One thread will be created for each partition of a  source.It reads data from source.

Writer thread: It will be created to load data to the target.

Transformation thread: It will be created to tranform data.

 72.What r the data movement modes in informatcia?

       Datamovement modes determines how informatcia server handles the charector data.U choose the datamovement in the  informatica server configuration settings.Two types of datamovement modes avialable in informatica.

    ASCII mode
    Uni code mode.

73. What r the out put files that the informatica server creates during the session running?

       Informatica server log: Informatica server(on unix)  creates a log for all status and error messages(default name: pm.server.log).It also creates an error log for error messages.These files will be created in informatica home directory.

Session log file: Informatica server creates session log file for each session.It writes information about session into log files such as initialization process,creation of sql commands for reader and writer threads,errors encountered and load summary.The amount of detail in session log file depends on the tracing level that u set.

Session detail file: This file contains load statistics for each targets in mapping.Session detail include information such as table name,number of rows written or rejected.U can view this file by double clicking on the session in monitor window

Performance detail file: This file contains information known as session performance details which helps U where performance can be improved.To genarate this file select the performance detail option in the session property sheet.

Reject file: This file contains the rows of data that the writer does notwrite to targets.

Control file: Informatica server creates control file and a target file when U run a session that uses the external loader.The control file contains the information about the target flat file such as data format and loading instructios for the external loader.

Post session email: Post session email allows U to automatically communicate information about a session run to designated recipents.U can create two different messages.One if the session completed sucessfully the other if the session fails.

Indicator file: If u use the flat file as a target,U can configure the informatica server to create indicator file.For each target row,the indicator file contains a number to indicate whether the row was marked for insert,update,delete or reject.

output file: If session writes to a target file,the informatica server creates the target file based on file prpoerties entered in the session property sheet.

Cache files: When the informatica server creates memory cache it also creates cache files.For the following circumstances informatica server creates index and datacache files.

  Aggreagtor transformation
  Joiner transformation
  Rank transformation
  Lookup transformation

74.In which circumstances that informatica server creates Reject files?

      When it encounters the DD_Reject in update strategy transformation.
       Violates database constraint
      Filed in the rows was truncated or overflowed.

75. What is polling?
It displays the updated information about the session in the monitor window. The monitor window displays the status of each session when U poll the informatica server

76. Can u copy the session to a different folder  or repository?

        Yes. By using copy session wizard u can copy a  session in a different folder or repository.But that
target folder or repository should consists of mapping of that session.
If target folder or repository is not having the maping of copying session , 
u should have to copy that maping first before u copy the session
77. What is batch and describe about types of batches?

        Grouping of session is known as batch.Batches r two types
        Sequential: Runs sessions one after the other
       Concurrent: Runs session at same time.

        If u have sessions with source-target dependencies u have to go for sequential batch to start the
sessions one after another.If u have several independent sessions u can use concurrent batches.
Whch runs all the sessions at the same time.

78. Can u copy the batches?        NO

79.How many number of sessions that u can create in a batch?  Any number of sessions.

80.When the informatica server marks that a batch is failed?

   If one of session is configured to "run if previous completes" and that previous  session fails.

81. What is a command that used to run a batch?       pmcmd is used to start a batch.

82. What r the different options used to configure the sequential batches?         Two options

        Run the session only if previous session completes sucessfully. Always runs the session.

83. In a sequential batch can u run the session if previous session fails?

    Yes.By setting the option always runs the session.

84. Can u start a batches  with in a  batch?
        U can not. If u want to start batch that resides in a batch,create a new independent batch and copy the necessary sessions into the new batch.

85. Can u start a session inside a batch idividually?   
      We can start our required session only in case of sequential batch.in case of concurrent batch
    we cant do like this.

86. How can u stop a batch?         By using server manager or pmcmd.

87. What r the session parameters?

     Session parameters r like maping parameters,represent values U might want to change between
     sessions such as database connections or source files.

       Server manager also allows U to create userdefined session parameters.Following r user defined
    session parameters.
                     Database connections
                     Source file names: use this parameter when u want to change the name or location of
                                                  session source file between session runs
                     Target file name :   Use this parameter when u want to change the name or location of
                                                   session  target file between session runs.
                     Reject file name :   Use this parameter when u want to change the name or location of
                                                  session reject files between session runs.

88. What is parameter file?
      Parameter file is to define the values for parameters and variables used in  a session.A parameter
    file is a file created by text editor such as word pad or notepad.
     U can define the following values in parameter file
         Maping parameters
         Maping variables
         session parameters

89. How can u access the remote source into U'r session?

     Relational source: To acess relational source which is situated in a remote place ,u need to
                                  configure database connection to the datasource.

     FileSource : To access the remote source file U must configure the FTP connection to the
                              host machine before u create the session.

     Hetrogenous : When U'r maping contains more than one source type,the server manager creates
                             a hetrogenous session that displays source options for all types.


90. What is difference between partioning of relatonal target and partitioning of file targets?

     If u parttion a session with a relational target informatica server creates multiple connections
      to the target database to write target data concurently.If u partition a session with a file target
      the informatica server creates one target file for each partition.U can configure session properties
      to merge these target files.

91. what r the transformations that restricts the partitioning  of sessions?

     Advanced External procedure tranformation and External procedure transformation: This
       transformation contains a  check box on the properties tab to allow partitioning.

     Aggregator Transformation: If u use sorted ports u can not parttion the assosiated source

    Joiner Transformation : U can not partition the master source for a joiner transformation

   Normalizer Transformation

  XML targets.

92. Performance tuning in Informatica?

      The goal of performance tuning is optimize session performance so sessions run during the available load window for the Informatica Server.Increase the session performance by following.

  The performance of the Informatica Server is related to network connections. Data generally moves across a network at less than 1 MB per second, whereas a local disk moves data five to twenty times faster. Thus network connections ofteny affect on session performance.So aviod   netwrok connections.

      Flat files: If u'r flat files stored on a machine other than the informatca server, move those files to the machine that consists of informatica server.
 Relational datasources: Minimize the connections to sources ,targets and informatica server to
  improve session performance.Moving target database into server system may improve session
  performance.
Staging areas: If u use staging areas u force informatica server to perform multiple datapasses.
Removing of staging areas may improve session performance.

U can run the multiple informatica servers againist the same repository.Distibuting the session load to multiple informatica servers may improve session performance.

Run the informatica server in ASCII datamovement mode improves the session performance.Because ASCII datamovement mode stores a character value in one byte.Unicode mode takes 2 bytes to store a character.

If a session joins multiple source tables in one Source Qualifier, optimizing the query may improve performance. Also, single table select statements with an ORDER BY or GROUP BY clause may benefit from optimization such as adding indexes.

We can improve the session performance by configuring the network packet size,which allows
data to cross the network at one time.To do this go to server manger ,choose server configure database connections.

If u r target consists key constraints and indexes u slow the loading of data.To improve the session performance in this case drop constraints and indexes before u  run the session and rebuild them after completion of session.

Running a parallel sessions by using concurrent batches will also reduce the time of loading the
data.So concurent batches may also increase the session performance.

Partittionig the session improves the session performance by creating multiple connections to sources and targets and loads data in paralel pipe lines.

In some cases if a session contains a aggregator transformation ,u can use incremental aggregation to improve session performance.

Aviod transformation errors to improve the session performance.

If the sessioin containd lookup transformation u can improve the session performance by enabling the look up cache.

If U'r session contains filter transformation ,create that filter transformation nearer to the sources
or u can use filter condition in source qualifier.

Aggreagator,Rank and joiner transformation may oftenly decrease the session performance .Because they must group data before processing it.To improve session performance in this case use sorted ports option.

92. What is difference between maplet and reusable transformation?

        Maplet consists of set of transformations that is reusable.A reusable transformation is a
    single transformation that can be reusable.

     If u create a variables or parameters in maplet that can not be used in another maping or maplet.Unlike the variables that r created in a reusable transformation can be usefull in any other maping or maplet.

 We can not include source definitions in reusable transformations.But we can add sources to a maplet.

Whole transformation  logic will be hided in case of maplet.But it is transparent in case of reusable transformation.

We cant use COBOL source qualifier,joiner,normalizer transformations in maplet.Where as we can make them as a reusable transformations.

93. Define informatica repository?

       The Informatica repository is a relational database that stores information, or metadata, used by the Informatica Server and Client tools. Metadata can include information such as mappings describing how to transform source data, sessions indicating when you want the Informatica Server to perform the transformations, and connect strings for sources and targets.

The repository also stores administrative information such as usernames and passwords, permissions and privileges, and product version.

Use repository manager to create the repository.The Repository Manager connects to the repository database and runs the code needed to create the repository tables.Thsea tables
stores metadata in specific format the informatica server,client tools use.

94. What r the types of metadata that stores in repository?

    Following  r the types of metadata that stores in the repository

   Database connections
   Global objects
   Mappings
Mapplets
 Multidimensional metadata
Reusable transformations
  Sessions and batches
  Short cuts
  Source definitions
 Target defintions
 Transformations

95. What is power center repository?

    The PowerCenter repository allows you to share metadata across repositories to create a data mart domain. In a data mart domain, you can create a single global repository to store metadata used across an enterprise, and a number of local repositories to share the global metadata as needed.

96. How can u work with remote database in informatica?did u work directly by using remote
      connections?

     To work with remote datasource u need to connect it with remote connections.But it is not
     preferable to work with that remote source directly by using remote connections .Instead u bring  that source  into U r local machine where informatica server resides.If u work directly with remote source the session performance will decreases by passing less amount of data  across the network in a particular time.

97. What r the new features in Informatica 5.0?

     U can Debug U'r maping in maping designer
    U can view the work space over the entire screen
    The designer displays a new icon for a invalid mapings in the navigator window
    U can use a dynamic lookup cache in a lokup transformation
    Create maping parameters or maping variables in a maping or maplet to make mapings more
     flexible
    U can export objects into repository and import objects from repository.when u export a repository object,the designer or server manager creates an XML file to describe the repository metadata.
The designer allows u to use Router transformation to test data for multiple conditions.Router transformation allows u route groups of data to transformation or target.
U can use XML data as a source or target.

Server Enahancements:

     U can use the command line program pmcmd to specify a parameter file to run sessions or batches.This allows you to change the values of session parameters, and mapping parameters and variables at runtime.

If you run the Informatica Server on a symmetric multi-processing system, you can use multiple CPUs to process a session concurrently. You configure partitions in the session properties based on source qualifiers. The Informatica Server reads, transforms, and writes partitions of data in parallel for a single session. This is avialable for Power center only.

Informatica server creates two processes like loadmanager process,DTM process to run the sessions.

Metadata Reporter: It is a web based application which is used to run reports againist repository metadata.

U can copy the session across the folders and reposotories using the copy session wizard in the informatica server manager

With new email variables, you can configure post-session email to include information, such as the mapping used during the session

98. what is incremantal aggregation?

    When using incremental aggregation, you apply captured changes in the source to aggregate calculations in a session. If the source changes only incrementally and you can capture changes, you can configure the session to process only those changes. This allows the Informatica Server to update your target incrementally, rather than forcing it to process the entire source and recalculate the same calculations each time you run the session.

99. What r the scheduling options to run a sesion?

    U can shedule a session to run at a given time or intervel,or u can manually run the session.

      Different options of scheduling

      Run only on demand: server runs the session only when user starts session                                         explicitly
      Run once: Informatica server runs the session only once at a specified date and time.
      Run every: Informatica server runs the session at regular intervels as u configured.
      Customized repeat: Informatica server runs the session at the dats and times secified in the                                      repeat dialog box.

100 .What is tracing level and what r the types of tracing level?

          Tracing level represents the amount of information that informatcia server writes in a log file.
     Types of tracing level
           Normal
           Verbose
           Verbose init
           Verbose data

101. What is difference between stored procedure transformation and external procedure transformation?

        In case of storedprocedure transformation  procedure will be compiled and executed in a relational data source.U need data base connection to import the stored procedure in to u'r maping.Where as in external procedure transformation procedure or function will be executed out side of data source.Ie u need to make it as a DLL to access in u r maping.No need to have data base connection in case of external procedure transformation.

102. Explain about Recovering sessions?

        If you stop a session or if an error causes a session to stop, refer to the session and error logs to determine the cause of failure. Correct the errors, and then complete the session. The method you use to complete the session depends on the properties of the mapping, session, and Informatica Server configuration.
Use one of the following methods to complete the session:
   Run the session again if the Informatica Server has not issued a commit.
   Truncate the target tables and run the session again if the session is not recoverable.
   Consider performing recovery if the Informatica Server has issued at least one commit.

103. If a session fails after loading of 10,000 records in to the target.How can u load the records from 10001 th record when u run the session next time?

    As explained above informatcia server has 3 methods  to recovering the sessions.Use performing recovery to load the records from where the session fails.

104. Explain about perform recovery?

      When the Informatica Server starts a recovery session, it reads the OPB_SRVR_RECOVERY table and notes the row ID of the last row committed to the target database. The Informatica Server then reads all sources again and starts processing from the next row ID. For example, if the Informatica Server commits 10,000 rows before the session fails, when you run recovery, the Informatica Server bypasses the rows up to 10,000 and starts loading with row 10,001.
        By default, Perform Recovery is disabled in the Informatica Server setup. You must enable Recovery in the Informatica Server setup before you run a session so the Informatica Server can create and/or write entries in the OPB_SRVR_RECOVERY table.

105. How to recover the standalone session?

      A standalone session is a session that is not nested in a batch. If a standalone session fails, you can run recovery using a menu command or pmcmd. These options are not available for batched sessions.

    To recover sessions using the menu:
1. In the Server Manager, highlight the session you want to recover.
2. Select Server Requests-Stop from the menu.
3.  With the failed session highlighted, select Server Requests-Start Session in Recovery Mode from the menu.

   To recover sessions using pmcmd:
1.From the command line, stop the session.
2. From the command line, start recovery.

106. How can u recover the session in sequential  batches?

     If you configure a session in a sequential batch to stop on failure, you can run recovery starting with the failed session. The Informatica Server completes the session and then runs the rest of the batch. Use the Perform Recovery session property

To recover sessions in sequential batches configured to stop on failure:

1.In the Server Manager, open the session property sheet.
2.On the Log Files tab, select Perform Recovery, and click OK.
3.Run the session.
4.After the batch completes, open the session property sheet.
5.Clear Perform Recovery, and click OK.

If you do not clear Perform Recovery, the next time you run the session, the Informatica Server attempts to recover the previous session.
If you do not configure a session in a sequential batch to stop on failure, and the remaining sessions in the batch complete, recover the failed session as a standalone session.

107. How to recover sessions in concurrent batches?

If multiple sessions in a concurrent batch fail, you might want to truncate all targets and run the batch again. However, if a session in a concurrent batch fails and the rest of the sessions complete successfully, you can recover the session as a standalone session.
To recover a session in a concurrent batch:
1.Copy the failed session using Operations-Copy Session.
2.Drag the copied session outside the batch to be a standalone session.
3.Follow the steps to recover a standalone session.
4.Delete the standalone copy.

108. How can u complete unrcoverable sessions?

     Under certain circumstances, when a session does not complete, you need to truncate the target tables and run the session from the beginning. Run the session from the beginning when the Informatica Server cannot run recovery or when running recovery might result in inconsistent data.

109. What r the circumstances that infromatica server results an unreciverable session?

        The source qualifier transformation does not use sorted ports.
        If u change the partition information after the initial session fails.
       Perform recovery is disabled in the informatica server configuration.
       If the sources or targets changes after initial session fails.
       If the maping consists of sequence generator or  normalizer transformation.
       If a concuurent batche contains multiple failed sessions.

110. If i done any modifications for my table in back end does it reflect in informatca warehouse or maping desginer or source analyzer?

   NO. Informatica is not at all concern with back end data base.It displays u all the information
   that is to be stored in repository.If want to reflect back end changes to informatica screens,
 again u have to import from back end to informatica by valid connection.And u have to replace the existing files with imported files.

111. After draging the ports of three sources(sql server,oracle,informix) to a single source qualifier, can u map these three ports directly to target?

 NO. Unless and until u join those three ports in source qualifier u cannot map them directly.